There is a vast amount of polymer composition applications wherein the elements or objects therefrom require having elastomeric properties, that is, to exhibit extensibility and flexibility properties allowing them to recover their shape after being considerably extended.
Due to the above, a great variety of materials having elastomeric properties have been developed over time, with styrene-butadiene copolymers being among the most renowned and widely used ones:
Although it is possible to find in the state of the art a great variety of elastomeric polymer compositions having various mechanical or physical properties such as hardness, tensile strength, or modulus of elasticity, among others, the compositions known so far lose their elastomeric properties with temperature, which limits the optimal performance thereof when they are to be used in high-temperature applications.
With the development of more effective polymerization catalyzers, such as the one depicted in the patent application MX 9801717, it has been possible to control the structure of polymers, allowing thus to obtain regularity in chains. Thus, in the case of styrene elastomers, syndiotactic polystyrene has been used in order to achieve beneficial results for the properties of the polymer compositions therefrom.
For instance, U.S. Pat. No. 5,260,394 depicts a syndiotactic polystyrene copolymer with inserts of olefin and/or dienic monomers exhibiting proper chemical and thermal resistance properties, in addition to allowing an appropriate processing and good compatibility with other compositions. The copolymers depicted therein aim to have materials with good processing by injection molding due to their low glass transition temperature.
Likewise, U.S. Pat. No. 5,352,727 depicts a syndiotactic polystyrene composition modified with rubber aiming to provide such composition with better processing properties when it is reprocessed after being used once, keeping its mechanical and heat decomposition resistance properties after being reprocessed.
Generally, other documents such as U.S. Pat. No. 6,046,275; U.S. Pat. No. 6,191,197; U.S. Pat. No. 5,352,727; U.S. Pat. No. 5,260,394; U.S. Pat. No. 5,543,462; and U.S. Pat. No. 5,777,028 use various mixtures of syndiotactic polystyrene with other polymers or copolymers allowing to modify the mechanical and processing properties of such a polymer compositions.
However, none of these documents introduce a composition having elastomeric properties at wide temperature ranges since, due to the nature of the compatibilizing agents normally used to obtain compositions in stereoregular polymers, such compositions cannot be used at low temperatures and therefore the use of this kind of materials continues to be limited to temperatures over −4° F.
According to the above, we have pretended to overcome the disadvantages of known elastomeric compositions by obtaining a polymer composition not also having elastomeric properties at wide temperature ranges, but which can be used at high temperatures and keeps its impact strength, chemical, mechanical, and wear resistance properties under high temperatures, in addition to keep its elastomeric properties at temperatures under −4° F.